RECOGNITION OF ALPHA-HELICAL PEPTIDE STRUCTURES USING HIGHPERFORMANCE LIQUID-CHROMATOGRAPHIC RETENTION DATA FOR D-AMINO-ACID ANALOGS - INFLUENCE OF PEPTIDE AMPHIPATHICITY AND OF STATIONARY-PHASE HYDROPHOBICITY

The reversed-phase HPLC behaviour of double D-amino acid replacement sets of amphipathic and nonamphipathic helix-forming peptides consisting exclusively of leucine, lysine and alanine residues was studied on different polymer-encapsulated silica-based stationary phases. Plotting the retention times versus the position of D-amino acid substitution gives a characteristic pattern showing decreased retention times in the helical region. The retention time profile obtained using an amphipathic alpha-helix is caused by disturbance of the preferred binding domain of the stationary phase-bound peptide. However, the effect is similar but less pronounced using a non-amphipathic helical peptide that is unable to interact by a preferred binding site. The results demonstrate that reversed-phase HPLC data for peptide analogues provide an indication event of a non-amphipathic helical structure in peptides.